Mark Prior's "Perfect"Pitching Mechanics

2009.3.12Updated 2015.03.03

One thing that is holding up the adoption of the science (and
yes sometimes art) of pitching mechanics analysis is the case of Mark Prior.
Pretty much whenever someone, whether it's me or someone else
like Kyle Boddy,
makes a point about some pitcher being an injury risk due to
their questionable pitching mechanics, someone inevitably jumps
in with a variation of...

In order to try to advance the discussion, and hopefully
increase the number of people who believe that there is in fact a relationship between pitching
mechanics and injury rates, let me tell you what I know about
the whole Mark Prior perfect pitching mechanics fiasco.

Who Said What, When?

In order to inject some facts into the debate, let's first go back
to the original sources. An
article in the December 2002 issue of Baseball Digest
written by Greg Couch contains the following comments about Mark
Prior and quotes by Tom House...

"Mark is the real deal," said Tom House, a longtime major
league pitching coach who worked privately with Prior for
years. "Of the hard throwers, he's right up there with the
(Nolan) Ryans, (Roger) Clemenses."...
House is a new-age coach, relying on coaching and playing
experience and also his Ph.D. in psychology. He has taken
all that science--computer, medical, nutritional and
psychological--can offer to come up with a plan for
developing pitchers...
"Mark has been exposed to, and taken advantage of, the
best research available," House said. "He has been the
poster child for what is, objectively, non-traditional
baseball knowledge. He's not going to fail."...
House films pitchers at 1,000 frames a second, then
downloads into his computer. That way, he can slow down a
pitcher's motion and find exactly where any non-productive
movements might be. Of 600 pitchers in House's computer, he
said, Prior has the best mechanics after Ryan, Clemens,
Randy Johnson and Curt Schilling...
His mental makeup, nutritional balance, everything else?
Off the charts...
"He has all the pieces," House said. "Nolan Ryan (who
worked with House) had some of the pieces. Other guys have
had some. Mark is the first to have them all.Objectively, he's a can't-miss."

I'm not certain, but this candidate is as good as any as the
origin of the "Mark Prior has perfect pitching mechanics" meme.

Mark Prior and Tom House

The problem with the article above is the first word of the
last line in the quote above.

Objectively.

The word "objectively" implies that there is some independence
between Tom House and Mark Prior, or at least Tom House's
analysis of Mark Prior's pitching mechanics.

The problem is that that isn't the case.

As is clearly stated in first quoted line of the article, Tom House was Mark
Prior's pitching coach and worked with him for years. As a
result, Tom House clearly has some skin in the game, and some
stake in Mark Prior's success, which makes him anything but an
impartial, objective observer. If Tom House was to criticize
Mark Prior's pitching mechanics, he would be criticizing himself
and his methods.

Consequently, what else would you expect Tom House to say?

Of course, the fact that the article relies so heavily on the words of a
clearly, and admittedly, non-objective analyst calls into
question the wisdom of the entire article and whether it should
ever have been published in the first case. Who uses as their
primary mechanics analysis source someone who success is so
closely tied to the success of the subject of the article?

That's very sloppy journalism.

Maybe with the word "objectively", Tom House was
making the case that the computer, and not his beliefs, was telling him
that Mark Prior was a can't miss prospect. However, anyone who
works with computer models knows that they are highly dependent
upon the assumptions that are built into them. In retrospect,
it's obvious that the assumptions that were used to build Tom
House's computer model were incomplete; they missed something
important and that something quite possibly led to Mark Prior's
problems.

Tom House and Will Carroll

Some people point to the work of Will Carroll as backing up
Tom House's claims about Mark Prior. See for example this quote
in this article in Baseball Prospectus...

Rany Jazayerli: I'm not sure I understand
why. Yes, he threw 126 pitches, and he's done that a lot
this year, but I've been led to believe by multiple
sources--as diverse as (Montreal Expos minor league pitching
coordinator) Brent Strom and our own Will Carroll--that
Prior's mechanics are as drop-dead perfect as they come. I'm
inclined to think that Prior is the Tom Seaver of our
generation, a pitcher capable of weathering high workloads
because 1) he has great mechanics and 2) he's so effective
that, even at eight innings a pop, he's unlikely to have to
throw more than 130 pitches at a time.

There are also these passages from
this article from ESPN.com
by Will Carroll and Nate Silver and ...

In the terminology of pitching biomechanics,
Mark Prior is a freak.

Stand near Prior in the Cubs' clubhouse, and you'll
see that his calves are roughly the size of an average
man's thigh. As Prior goes through his delivery and
pushes off the rubber, the strong muscles drive his body
forward. While the gyrations of a windup like
Dontrelle Willis or Hideo Nomo make it difficult to assess their
mechanics and add to the deception a hitter faces,
Prior's efficient delivery disguises the linear
driveline his pitches come through.

While we all know that the quickest path between two
points is a straight line, few pitchers can regularly
bring a baseball in a straight line to home plate.

Prior
can.

According to Gary Heil of the National Pitching
Alliance (sic), Prior was tested using high-tech Matrix-like
technology to assess his mechanics.

"No one else was even close," Heil said. "He's the
model; he's perfect."

Dr. Mike Marshall is a former Cy Young Award winner
who has completed extensive scientific studies of the
pitching motion. Using basic, Newtonian principles of
inertia and reaction, Marshall's teachings show that
Prior's controlled delivery is near ideal.

He'd be the Six Million Dollar Bionic Pitcher. Except
that when his salary arbitration payday comes up, he'll
undoubtedly make a lot more than that.

The problem is that Will Carroll also isn't totally objective
when it comes to Mark Prior. Will Carroll and Tom House are
apparently friends, and that friendship seems to have grown out
of the writing of Saving The Pitcher. In Saving The
Pitcher,
Will Carroll talks at length about Tom House, Mark Prior, and
Mark Prior's pitching mechanics. If Will Carroll were to
criticize Mark Prior's pitching mechanics, he would be de facto
criticizing the conclusion he drew in his own book, and that's something that authors tend not
to do.

Tom House and Paul Nyman

I don't know for a fact where Mark Prior's pitching mechanics
came from. However, given that Mark Prior's pitching
mechanics so closely resemble the pitching mechanics of
Anthony
Reyes and
Ian Kennedy, two other USC
and Tom House products from the same era,
that says to me that they were most likely taught to him rather
than being totally natural. I do know for a fact that Paul Nyman has talked
for a number of years about the idea of breaking the hands with
the elbows and the
Inverted W, and I would
not be surprised if Tom House was influenced by the work of Paul
Nyman and taught Mark Prior his arm action.

2009.3.12 UPDATEI just came across a very
interesting piece by Jeff Passan entitled
Pristine Mechanics Caused Prior Pain that adds some more
detail about who did what to Mark Prior and when. Some of the
more interesting and relevant quotes are...

When he watched the gangly Prior as a sophomore in high
school, (Tom) House saw the perfect specimen to build into
the ultimate pitcher. For the next six years, he put Prior
on a specific diet, ran blood work regularly, schooled him
in mental acuity and, most important, imparted all of the
lessons he had learned from high-speed-video and computer
studies about proper mechanics to avoid injury.

“Because he was a computerized athlete,” House said,
“he was supposed to be perfect.”

This helps to reinforce the idea that Tom House was heavily
involved in the process of molding Mark Prior's mechanics and
that Mark Prior likely didn't just come up with the Inverted W
all on his own.

About The Author

Chris O'Leary never played baseball beyond grade school due
to a shoulder injury suffered due to poor pitching mechanics. As
a result, he is focused on ensuring that what happened to him
doesn't happen to anybody else.
The Epidemic is one way he hopes to achieve that goal.